Why is it important to dispose of or use elements properly ?

If they aren't disposed of safely, those chemicals can pose a safety hazard to people, animals and the environment. In addition to contaminating soil, hazardous wastes can pollute the air and leach into water sources. ... They are considered hazardous because they also contain lead.

Explanation:

Carrying out investigations in a responsible way can reduce pollution and waste. It can also ensure that natural resources and other materials will be available for future generations. reusing: Glass beakers can be washed and used again.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.

that's what i got you can count the number of atoms